Atoms, Elements, Molecules, and Ions and

Question 1

In the fifth century BC the Greek philosopher _____ expressed the belief that all matter consists of very small, indivisible particles, which he named ____
(meaning uncuttable or indivisible)

Answer 1

Democritus
atomos

Question 2

Explain John Dalton’s atomic theory (4 hypotheses)

Answer 2

1. Elements are composed of extremely small particles called atoms.
2. All atoms of a given element are identical, having the same size, mass, and chemical properties. The atoms of one element are different from the atoms of all other elements.
3. Compounds are composed of atoms of more than one element. In any compound, the ratio of the numbers of atoms of any two of the elements present is either an integer or a simple fraction.
4. A chemical reaction involves only the separation, combination, or rearrangement of atoms; it does not result in their creation or destruction

Question 3

To form a certain compound, we need not only atoms of the right kinds of elements, but ____ as well.

Answer 3

specific numbers of these atoms

Question 4

Define Proust’s Law of Definite Proportion

Answer 4

different samples of the same compound always contain its constituent elements in the same proportion by mass (same ratio of elements)

Question 5

Define Law of Multiple Proportion

Answer 5

if two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the
other element are in ratios of small whole numbers

Question 6

Define law of conservation of mass

Answer 6

matter can be neither created nor destroyed

Question 7

Define an atom and subatomic particles

Answer 7

the basic unit of an element that can enter into chemical combination

atom was both extremely small and indivisible but proven in the 1850s that it possesses internal structure.

the internal structure is composed of even smaller particles called subatomic particles namely, electrons, protons, and neutrons

Question 8

the emission and transmission of energy through space in the form of waves

Answer 8

radiation

Question 9

Who discovered the charge of electron? What is the numerical value?

Answer 9

-1.6022 x 10^-19 C
Robert Andrews Millikan

Question 10

Discovered and coined the term X-rays. Explain the name X-rays.

Answer 10

Wilhelm Röntgen

Unusual cathode rays could not be deflected by a magnet, they could not contain charged particles as cathode rays do. Called X-rays because of unusual nature.

Question 11

How was radioactivity termed?

Answer 11

Suggested by Marrie Curie (student of Antoine Becquerel)

Rays from uranium compound cannot be deflected by magnet and happen spontaneously.

Question 12

Explain the types of radiation produced by radioactive decay

Answer 12

1. Alpha rays - consists of positively charged particles
2. Beta rays - consists of negatively charged particles
3. Gamma rays - no charged and not affected by an external field

Question 13

Explain Thomson’s plum-pudding model of atom

Answer 13

atom could be thought of as a uniform, positive sphere of matter in which electrons are embedded like raisins in a cake

Question 14

Explain Rutherford gold foil experiment

Answer 14

majority of alpha-particle (+ charged) passed through the gold foil but every now and then, some rays are deflected and even came straight back to the emitter.

it is because the positive charge (protons) of an atom is concentrated at the center called nucleus and most of the atom is empty space.

Question 15

How James Chadwick discovered neutrons?

Answer 15

A thin sheet of beryllium was bombarded with alpha-particles which resulted to the emission of very high energy radiation similar to gamma rays.

Question 16

the number of protons/electrons in the nucleus of each atom of an element

Answer 16

atomic number (Z)

Question 17

the total number of neutrons and protons present in the nucleus of an atom of an element

Answer 17

mass number (A)

Question 18

Formula for neutrons

Answer 18

Neutrons = A - Z

Question 19

atoms that have the same atomic number but different mass numbers

Answer 19

isotopes

Question 20

(T/F) Neutrons do not take part in chemical changes under normal conditions

Answer 20

True

Question 21

(T/F) Isotopes of the same element have unique chemistries, forming the same types of compounds and displaying similar reactivities

Answer 21

False.

The chemical properties of an element are determined primarily by the protons and electrons in its atoms

Question 22

(T/F) A molecule is always a compound.

Answer 22

False. Not all molecules are compounds

Compound - two or more elements
Molecule - two or more atoms

Question 23

Differentiate monoatomic, diatomic, and polyatomic molecule.

Answer 23

Monoatomic - single atom (noble gases)
Diatomic - two atoms (halogens)
Polyatomic - more than two atoms

Question 24

(T/F) Protons may be lost or gained to form an ion

Answer 24

False. Only electrons may be lost or gained

Question 25

___ is one of two or more distinct forms of an element

Answer 25

allotrope

Question 26

Differentiate organic and inorganic compounds

Answer 26

Organic compounds - compounds that contain carbon atoms Inorganic compounds - all other compounds exemption: CO, CO2, CS2, CN-, CO3, HCO3

Question 27

What is Stock system of nomenclature?

Answer 27

using Roman numerals to indicate charges MnO = manganese(II) oxide

Question 28

acids that contain hydrogen, oxygen, and another element (central element)

Answer 28

oxoacids

Question 29

proposed the theory of electromagnetism and established connection between light and electromagnetic waves

Answer 29

James Clerk Maxwell

Question 30

proposed that electricity is made up of discrete negative particles called electrons

Answer 30

George Stoney

Question 31

conducted experiments with cathode ray tubes, demonstrating that cathode rays carry a negative charge

Answer 31

William Crookes

Question 32

used cathode ray tubes to study canal rays which had electrical and magnetic properties opposite to electron

Answer 32

Eugene Goldstein

Question 33

discovered that certain materials glowed when exposed to cathode rays and named these X-rays

Answer 33

Wilhelm Roentgen

Question 34

discovered radiation by studying the effects of uranium on photographic film

Answer 34

Henri Becquerel

Question 35

used cathode ray tubes to determine the charge-to-mass ratio of electron

Answer 35

Joseph John Thomson

Question 36

discovered alpha, beta, and gamma rays in radiation

Answer 36

Ernest Rutherford

Question 37

Theorized that radioactive particles cause atoms to break down, releasing radiation in the form of energy and subatomic particles. Discovered radioactive elements polonium and radium

Answer 37

Pierre and Marie Curie

Question 38

proposed the idea of quantization to explain how hot, glowing object emits light

Answer 38

Max Planck

Question 39

discovered that there appeared to be more than one element at certain positions on the periodic table ____ coined the term "isotopes" for these elements

Answer 39

Frederick Soddy Margaret Todd

Question 40

discovered that noble gases have stable electron configurations

Answer 40

Richard Abegg

Question 41

developed the theories of relativity and hypothesized about the particle nature of light

Answer 41

Albert Einstein

Question 42

invented a device capable of detecting alpha particles

Answer 42

Hans Geiger

Question 43

determined the charge of electron through his oil drop experiment

Answer 43

Robert Millikan

Question 44

conducted the alpha particle experiment and established that nucleus was very dense, very small, and positively charged

Answer 44

Ernest Rutherford

Question 45

developed an atomic model which describes electrons travelling in orbits around nucleus

Answer 45

Niels Bohr

Question 46

discovered that number of protons (wavelengths of X-ray emission) in an element determined its atomic number

Answer 46

Henry Moseley

Question 47

proposed that electrons exhibit wave-particle duality

Answer 47

Louis de Broglie

Question 48

developed an equation which describes how quantum state of a system changes over time

Answer 48

Erwin Schrodinger

Question 49

Describe Law of Triads proposed by ___

Answer 49

atomic weight of middle element in certain triads was the average of atomic weights of other two elements Johann Dobereiner

Question 50

Describe Law of Octaves proposed by ____

Answer 50

states that when elements are arranged by their atomic weight, every eight element exhibits similar properties John Newlands

Question 51

studied the periodic behavior and repeating patterns among elements such as the relationship between atomic volume and relative atomic mass of 28 elements

Answer 51

Lothar Meyer

Question 52

Define Periodic Law proposed by ____

Answer 52

states that the properties of elements are periodic functions of their atomic masses. His periodic table includes 63 known elements Dmitri Mendeleev

Question 53

suggested that the number of charges in an elements atomic nucleus is exactly equal to the element's place on Mendeleev's table

Answer 53

Antonius van de Broek

Question 54

discovered 10 transuranium elements that earned him a share of 1951 Nobel Prize in Chemistry

Answer 54

Glenn Seaborg

Question 55

Two people to have an element named after while still alive

Answer 55

Glenn Seaborg (Seaborgium) and Yuri Oganessian (Oganesson)

Question 56

Elements with common allotropes (5 common and others)

Answer 56

Carbon (C) Sulfur (S) Tin (Sn) Oxygen (O) Phosphorus (P) Boron (B) Nitrogen (less common/ extreme conditions) Arsenic (As) Antimony (Sb) Iron (Fe) Cobalt (Co) Plutonium (Pu)

Question 57

Groups in Periodic Table

Answer 57

1. Alkali Metals 2. Alkaline Earth Metals 3-12. Transition Metals 13. Boron Group (Icosagens) 14. Carbon Group (Crystallogens) 15. Nitrogen Group (Pnictogens) 16. Oxygen Group (Chalcogens) 17. Halogens 18. Noble Gases Z=57-71: Lanthanides (Rare Earth elements) Z= 89-103: Actinides Z=104-118: Transactinides

Question 58

Differentiate malleability and ductility

Answer 58

Malleability - ability to form sheets and compressed Ductility - ability to form wires and stretched